fitter



w. c. PITTE R. MACHINE FOR GRINDING AND LAIFING SLIP AND GAP GAGES ANDTHE LIKE. APPLICATION FILED FEB-5.19IL

1 ,8 1 6,506, v PatentedS ept. 16, 1919.

4 SHEETS-SHEET I.

5 a. L? i it],

'w. c. PITTER. I MACHINE FOR GRINDING AND LAPPING SHP AND GAP GAGES ANDTHE- LIKE.

- APPLICATION FILED FEB- 5.191].

1,316,506. Patented Sept. 16,1919.

4 SHEETS-SHEET 2.

I 3 A A if A I W. C. PITTEII.

MACHINE FORISRINDING AND LAPPING SLIP'AND GAP GAGES AND THE LIKE.

APPLICATION FILED FEB. 5.1911.

Patented Sept. 16, 1919.

4 SHEETS-SHEET 3.

'THI: COLUMBIA I'LANOGRAPHI 00-, WASHINGTON. Ix C.

W. C. PITTER. MACHINE FOR GRINDING AND LAPPING SLIP AND GAP GAGES ANDTHE LIKE.

APPLICATION FILED FEB. 5.1!!!!v Patented Sept. 16, 1919.

4 SHEETS-SHEET 4.

Ewe r2 for Wa 6&4

. UNITED STATES PATENT OFFICE.

WALTER CHARLES PITTE-R, OF LONDON, ENGLAND.

MACHINE FOR GRINDING AND LAPPING SLIP AND GAP GAGES AND THELIKE'. I

Specification of Letters Patent.

Patented Sept. 16, 1919.

Application filed February 5. 1917. seriarno. 146.824.

To all whom it may concern 2 Be it known that I, WALTER CHARLES Prr-TER, a subject of the King of Great Britain, and a resident of London,England, have invented certain new and useful Improve ments in Machinesfor Grinding and Lapping Slip and Gap Gages and the like, of which thefollowing is a specification.

This invention relates to an improved machine for grinding and lappingslip and gap gages and the like, and has reference particularly tomachines of that general type wherein the grinding or polishing memberis given a compound movement such as a combined rotary and reciprocatorymovement.

The object of the .present invention is to make it possible to finishgrinding and lapping slip and gap gages, and other such narrowflatsurfaces, to a fine degree of accuracy by machine, in a more or lessautomatic manner, in a fraction of the time at present occupied by hand.

The invention consists broadly of a machine having a combination, meansfor holding the workin operative relation with the laps or grindingsurfaces which extend completely across one dimension of the work, andmeans for imparting to the laps a compound movement such as will insurethe laps passing completely over the whole surface being treated at eachcomplete move ment.

A feature of the invention which'is of importance is the provision of amagnetic chuck for holding the work so arranged that the work can beinserted in position and a switching on of the current will result inthe firm gripping of the work in the chuck and also the firm adhesion ofthe chuck-to the bed of the machine.

A further feature resides in the provision progressive movement so thatin effect a polnt on the lap or laps inscribes a series of progressivecurves and loops in both a forward and rearward direction, which isclosely approxim ting to the movement made by a man when lapping byhand, or a backward and forward movement comblned with a side to sidemovement of the 'la' which gives a zig-zagpath may be provided for.

In order that the inventionmay be more readily understood and carriedinto practice reference is hereby made to'the accompanying drawingswherein Flgure 1 is a side elevation of amachine designed for gap gages.

Fig. 2 is a plan ofFig. 1.

Fig. 8 is a detail view showing a lap support modified for particularuse.

Fig. 4 is an enlarged view of adjustable strips or guides.

Fig, 5 is a detail of the eccentric device in front and side elevation.V

Fig. dis a detail of-parallel strips.

Fig. 7 is a front elevational view of a machine designed for slipgages.

Fig. 8 is a plan of Fi 7.

Fig. 9 is an end elevation of Fig. 7.

Fig. 10 is a detail perspective view of the la s engaging the Work.

eferring to the drawings, and more particularly to Figs. 1' 1306inclusive the numorals land 2 designate a pair of hardened strips orguides between which the laps 3 .and 4 work. The gage, or work, 5 'to beoperated upon is held by means of a magnetic chuck 6 at apositionbetween the said strips or guides,

The laps 3 and it consisting of strips of metal, or other material, aremounted at each end on spindles 7 and 8, and aremain-- tained pressedagainst'the hardened guides 1 and 2 by means ofsprings 9 and 10. If

desired a further spring may be introduced between the laps at thelrcenter, in order to counteract any tendency to flexibility.

The two shafts or spindles 7 and 8 are each secured at each end bymeans-of suitable thimbles or open ended ferrules 11 to eccentric pins12, carried by circular rotatable disks 13 mounted on slides 14 as shownin'Figs. 1 ends. Provision is made for varying the eccentricity ofthepins 12, and consequently the rotary movement of the rods 7 and 8, and:for' this purpose the disks 13 are slotted" at '15; asJshoWn in Fig. 5;

and in order that the positions of the four pins 12 may exactlycorrespond a scale 16 is attached to each slot 15 and a gage mark toeach pin 12. The slides 14 work in guides 17 and each carries twosprocket wheels 18 and 19 which are mounted on the same shafts as thedisks 13, so that rotation of the sprocket wheels 18 and 19 will impartc1rcular motion to the laps 3 and a through the medium of the pins 12and the spindles 7 and 8. The spindles of the sprocket wheels 18 areeach connected by means of a connecting rod 20 to an eccentric pin 21carried by a disk 22 mounted on a driven shaft 28. A driven shaft 24carries a sprocket wheel 25 coupled to the sprocket wheel 26 on theshaft 23 by means of an endless chain 27; and a wheel 28 is coupled to awheel 29 on the driving shaft 30 by means of an endless chain 31. Theshaft 30 also carries a sprocket wheel 32, and an endless chain 33couples this wheel to the wheels 18 and 19. The shaft 30 is driven bymeans of belt gear ing on the pulley 3 1. The structure is mounted on abase plate 35 supported on uprights 36. The guides 17 are carried on theends of vertical members 37 which are slotted at their centers as at 38in order that they may accommodate, and be adjusted on, pins 39projecting from the base plate 35, thus permitting the vertical heightof the laps 3 and 1 to be varied at will.

Members 40 fixed to the base plate are provided, as shown particularlyin Fig. 1, to serve as guides for the adjustable members 37 which areprovided with index lines to register with scales 40* carried by themembers 10. The shaft 30 is'journaled in the lower ends of the members37 so that the coupled wheels 18, 19 and 32 rise in unison whenadjusted. Members ll similar to the members 37 carry the shafts 23 and 21, and these members work in guides 42 exactly similar to the guides 40,so that accurate vertical adjustment can be made to the laps and theirdriving mechanism.

The magnetic chuck I prefer to use for holding gap gages consists of twoseparate units 13 and 44:, each h.ving a coil wound on it, andpreferably provided with a spring or springs, as indicated at 45 tobring thesides loosely together, so that when the gage, or other work isplaced between them and the current switched on, the two units and thework become one horse shoe magnet, and thus the work and the chuck arefirmly held down to the table, or base plate 35.

The hardened strips 1 and 2 are fixed to guides 4:6 which are shownadjustable by means of slots and pins 47 and 48 but which may beadjusted in any known manner such, for instance, as by means of screws.The table, or base plate, 35 is provided with an upstanding member 49having a true edge to which the true edge of the guides 46 are held up,thus assuring the parallelism of the guides and the laps. The hardenedstrips 1 and 2 may be made adjustable as shown in Fig. 4:, where eachstrip comprises two wedge shaped members 1 and 1 having a screwadjustment 1.

A quick means is provided for removing the laps from the work forpurposes of inspection, and when the thimble device 11 aforesaid isemployed, the thimble can be moved from coupling position from one ofthe rods 7 or 8 and the other then becomes a hinge about which the lapscan be lifted out of the way.

If it is desired to use the machine to lap the ends of slip gages, thelaps 3 and 1 are mounted on the spindles 7 and 8 in the manner shown inFig. 3. Two springs 50 and 51 are used, one on the outside of each lapand distance pieces in the form of sliding collars 52 and 53 keep themin compression, and in this case the guide will be placed between thelaps.

Adjustable parallel slips 53 and 5&1 may be used to set the workcorrectly in the chuck, in line with the guides. These parallels are setto the size of the work to be lapped, the gap gage would be forced onthe center, the parallels then are set up to one pair of guides, and theother pair of guides brought up to it and, fastened, then the work andguides are all in correct relation to one another. Then by bringing thechuck up to the work and switching on the current, the work is held inplace.

It will be clear from the connections and gearing described that acombined circular motion is imparted to the laps which is similar to themovement used in lapping by hand, and imparts a very accurate and finelyfinished surface to the work.

When it is desired to lap a great number s of thin slips at the sametime, and when only one side can be done at a time, I may employ what Icall a single or modification. This modification of the machine has onlytwo fixed guides, that is one at each side of the machine with the lapresting on them, the chuck in this case being raised or lowered to suitthe different thickness of slips being operated on, the said chuckhaving a long straight edge attached for accurate setting of the chuckin relation to the guides. A machine embodying these features is illustrated in Figs. 7, 8 and 9, wherein the numeral 55 designates the mainbody of the machine. The magnetic chuck 56 is a single member providedwith a long straight edge 57, and a bolt, or projection 58, adapted toslide in a slot 59 in the main standard 55 and be secured in anyposition therein by means of a nut 60. The work 61 is placedon the faceof the chuck and is magnetically bound thereto when the current isswitched on. r

63 and 64, and the long straight edge 57 of the chuck is positionedparallel thereto by micrometer gages. The guides 63 and 64: arerelatively far apart so that any slight inaccuracy of the setting willbe quite inappreciable over the area of the work.

Two pins 65 each carried eccentrically on disks 66 cooperate with, orare secured to the lap. The disks 66 are carried on the underside of theslide 67, and concentric with each disk, but carried on the other sideof the slide is a sprocket wheel 68. There are two other sprocket wheelson the upper side of the slide and all four wheels 68 are coupled bymeans of an endless chain 69 driven by a sprocket wheel 70. The wheel 70is mounted on a shaft 71 journaled in brackets carried by the mainmember 55 and driven by means of a belt gearing with the pulley 7 2.Thus circular motion is imparted to the lap 62. The slide 67 is providedwith slots and bolts 73 and 74, and connect-' ed by means of a rod 75with an eccentric pin carried by a disk 76 rotating on the spindle 77,which is driven by means of a belt and pulley 78. Thus reciprocatingmovement is imparted to the lap 62. In this case the motion of the lapwill be slightly difierent from that described in relation to Figs. 1and 2, as a lost motion will occur during one direction of movement ofthe slide owing to the fact that the rotation of the wheels 68 and 71are always in the same direction, and it will be clear that for onedirection of the running the reciprocating motion aids the rotarymotion, and for the other direction retards it so that there will be alost motion for one direction of operation. This fact however is in noway detrimental to the efiiciency of the machine and the lapped surfaceis in every way equal to that obtained from the motion described inrelation to Figs. 1 and 2. p

In 'place of the chain gearing described I may use bevel or othergearing designed to insure the desired operation.

It will be appreciated that this machine can be used for truing narrowsurface plates and other surfaces of a like nature, and by using filesin place of the laps it can be used as a filing machine for soft work.

\Vhat I claim and desire to secure by Letters Patent is 1. An improvedmachine for grinding and lapping gap and slip gages and other suchnarrow flat objects, comprising in combina tion, means for holding thework in operative relation to the laps, a bodily movable lap carryingstructure, laps carried by said structure and extending at all timescompletely across one dimension of the work, means for moving the lapcarrying structure bodily and means for imparting a further movement tothe laps relative to their carrying structure such as will insure thelaps passing over the whole surface of the work at each of the movementsof the laps relative to the lap carrying structure.

-2. In a grinding and lapping machine, the combination of a bodilymovable lap carrying structure, laps carried by said structure andextending at all times completely across one dimension of the work,means moving the lap carrying structure bodily, means for imparting afurther movement to the laps relative to their carrying structure suchas will insure the laps passing over the whole surface of the work ateach of the movements of the laps relative to the lap carryingstructure, and means for holding the work stationary relative to the lapcomprising a magnetic chuck which, upon energization, grips the work andis simultaneously held to the bed of the machine.

3. In a grinding and lapping machine, the combination of a bodily movable lap carrying structure, laps carried by said structure and extendingat all times completely across one dimension of the work, rods, crankpins, means for detachably connecting said rods and crank pinscomprising sliding ferrules or thimbles, and laps mounted upon saidrods, means moving the lap carrying structure bodily, means forimparting a further movement to the laps relative to their carryingstructure such as will insure the laps passing over the whole surface ofthe work at each of the movements of the laps relative to the lapcarrying structure, and means for holding the work sta tionary relativeto the lap comprising a magnetic chuck which, upon energization, gripsthe work and is simultaneously held to the bed of the machine.

4. In a grinding and lapping machine, the combination of a bodilymovable lap carrying structure, laps carried by said structure andextending at all times completely across one dimension of the work,means moving the lap carrying structure bodily, adjustable guides forsaid laps formed with hardened faces to which the laps work, means forimparting a further movement to the laps relative to their carryingstructure such as will insure the laps passing over the whole surface ofthe work at each of the movements of the laps relative to the lapcarrying structure, and means for holding the work stationary relativeto the lap comprising a magnetic chuck which, upon energization, gripsthe work and is simultaneously held to the bed of the machine.

In testimony whereof I aflix my signature.

WALTER CHARLES PITTER.

cm" 0! thll patent may be obtained for five cents each, by addressingthe "Gommissioner of Patent! Washington, D. G.

